[Alexy] wanted to take this idea further and make it automatically spin on a rotated axes. He built a rotation assembly that was basically a motor, hung off-center, attached at the center of the globe. He had to power it via a coil hidden in the base unit, so that it could remain light enough to float. He did a fantastic job and the final product seems like it is the true way it should have been sold.

Check out a video of it in action after the break. We actually like the spinning ring, when he’s testing it, just as much as the final spinning globe.

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To me it looks like he just took the off the shelf globe that was already floating and rotating and shifted all the bits inside the globe to make it tilted. Its not clear why he would have to tune the induction coil, unless adjusting the tilt meant it needed to be re-calibrated. I don’t think he “made” any of it. Just adjusted.

So is it the magnetic field that holds onto the floating base and prevents it from rotating in the opposite direction? I was wondering why the base didn’t go one way while the globe went the other way like a helicopter without a tail rotor.

The globe rotates because of the conservation of angular momentum. The motor inside rotates one way, and the ‘frictionless’ globe will rotate the OTHER way, because angular momentum has to be conserved.

The globe rotates slower than the spinning motor rod because the globe is far heavier. The magnets beneath don’t resist the rotation at all.

This is an old comment, but its pretty high up and onone has responded, so I thought I should.

This is not the case. No matter how long you look at the globe, it will not spin in the opposite way to the motor (although it WILL spin).

The reason that the globe wont spin in the opposite way is indeed due to the magnets and the control system. For the globe to spin in the opposite direction, there would need to be a vertical component to the globe spin, as the motor spin has a vertical component. It cannot spin vertically, because when it lifts a little bit, the system will detect this and reduce the field strength, causing the magnetic field to weaken until gravity counteracts the force from the motor rotation. If the system was in a low gravity environment, the whole contraption would actually start to spin vertically (albeit very very slowly). The globe will, however, slowly spin in the horizontal plane.

This may be what beardysam meant, but if so he did not explain very well.

The instant I saw this I started thinking how cool it would be to have it rotate once a day with a bright light source illuminating one side. Then I was trying to come up with a way to add a moon that slowly orbited. Then I was picturing how one might have the whole thing move around a scale sun and how this might be elegantly incorporated into the architecture, perhaps a large circular room with a counter around the perimeter. Then I realized I was daydreaming.

i was imaging something much more complicated and wondering how he could pull it off. then i watched the video. angled floating internal motor powered by inductive coupling FTW! that is awesome. you could recreate the entire solar system on a big enough table, bases moving on tracks underneath, and put it in a museum. but i would just like to have it built into a desk. doesn’t have to be the earth.. power some LEDs via the inductive coupling as well, people would buy that shit up. you sir, are a genius :D

I’d really like to see a light added to this that represents the sun. And then control the motor so it’s in tune with the Earth’s rotation. So one could tell what areas of Earth where in sun and what parts weren’t. Mostly just because it would be awesome! I’d be tempted to buy something like this hack if it was made. The other globes just don’t seem as cool to me.

I love it!
It looks like the heavier globe is closer to the base. Is there even room for the shiney domed cover? Speaking of that, it is likely the cover (metal surface on plastic) will interefere with the induction field.
” I need more power!”

But he doesnt say the main thing:
How do you attach the power supply or the electric system to the magnetic base to keep it energized. That is the main secret. So you need to buy the Globe first and then apply the hack, but you cannot build one from scratch.

Erik: If you want the globe to rotate in time with the Earth the solution is even simpler than this – instead of a motor and inductive pickup simply attach the hour hand of a clock mechanism to the tilted equitorial ring. Of course you will need a 24hour clock, not a regular 12hour clock – or replace the 32KHz crystal in the 12Hr clock with a 16KHz crystal. :)